1. Field of the Invention
The present invention relates generally to form works for containing liquid concrete while it hardens, and more particularly to form works using bridge ties to connect opposing planar panels for forming concrete walls.
2. Prior Art
Form works made from plastic blocks connected by ties are well known in the construction industry for containing wet concrete as it dries. U.S. Pat. No. 3,788,020 observes that removal of forms requires considerable time, and teaches away from the use of removable wall forms by describing polystyrene panel-blocks interconnected by ties which keep the panels in place after they have served the purpose of containing wet concrete. In that patent, as noted by U.S. Pat. No. 4,655,014, using tie members fitted into pre-formed slots or grooves in the side walls results in the side walls being considerably weakened, and accordingly provides dovetail interface joints for connecting ties to the insides of wall forming panels. U.S. Pat. No. 4,706,429 describes ties with T-shaped ends which slide into polystyrene panel slots with shoulders underneath to absorb potential shocks to the panels when wet concrete is dumped into the form. U.S. Pat. No. 4,730,422 provides a similar system of ties and panels with indicia marks on the outer sides of the panels over tie ends hidden inside the panels as guides for sinking anchors for additional wall coverings, but the indicia marks do not necessarily assure that screws or other anchors will penetrate directly into tie ends.
The above prior art seeks to make more convenient and stronger form systems by using ties which become permanently imbedded in both the concrete and in the side panels. Once cemented in place, the panels cannot normally be removed if desired to expose the concrete inside.